The invention relates to a method of wrapping reams of paper and to equipment for the implementation of such a method, suitable in particular for large size reams.
Conventionally, large size reams (typically ISO A0) are wrapped using a machine consisting essentially in a moving surface along which the reams advance, and above the surface, a succession of stations by which each ream is wrapped; the first such station serves to draw out a given length of wrapping paper into a position such that it will be impinged on by the leading face of the advancing ream, whereupon the continued advance of the ream along the moving surface causes the wrapping paper to be flattened against the top and bottom sheets of the stack.
At the next station, the wrapping paper is cut to size and, at the same time, adhesive is sprayed by an adjacent station onto the cut edge of the paper already part-enveloping the stack, in such a way as to permit of fastening the wrapping into a sheath around the larger faces of the ream. The subsequent fastening operation, in which the gummed edge and the opposite edge of the wrapping are flattened and overlapped, is performed by an additional moving unit designed to follow the ream forward, with all the attendant drawbacks such a solution suggests, most notably the difficulty in making the wrapping paper tight and the degree of precision obtainable in overlapping the edges.
Thereafter, the smaller end flaps of the wrapping are flattened and secured at a further station of the machine by means of conventional fixed folding elements.
This particular method of wrapping large size reams betrays certain drawbacks: the manner in which the wrapping paper is folded around the ream tends to be imprecise, as aforementioned, or at least the paper is not properly tightened over the advancing stack of sheets; moreover, the gum is applied to a part of the wrapping paper already flattened over the ream and with the ream itself in movement, an operation liable not only to occasion positioning error but also to leave the topmost sheet of the ream fouled and subsequently unfit for use as a result.
Given the size of the reams and the succession of work stations incorporated, a machine capable of implementing the above method must be of notable proportions both in length and height, a factor tending also to increase its costs of construction and transportation.
Accordingly, the object of the present invention is to overcome the aforementioned drawbacks by setting forth a swift, accurate and practical method of wrapping reams, and relative equipment suitable for its implementation, such as will also guarantee a secure and faultless application of gum to the edge of the wrapping paper.